package com.yzh.stringbuilder;

/**
 * @author 于振晗
 * @title: TestStringBuilder
 * @description: TODO builder
 * @date 2020年08月31日
 * @path com.yzh.stringbuilder
 */
public class TestStringBuilder {
    public static void main(String[] args) {
        StringBuilder builder = new StringBuilder();
        System.out.println(builder.length()+"\t"+builder.capacity());
        builder.append("大兴区亦庄开发区");
        System.out.println(builder.length()+"\t"+builder.capacity());
        builder.append("科创十四街");
        System.out.println(builder.toString());
        System.out.println("hamburger".substring(4, 8));

        String str=null;
        str.concat("abc");
        str.concat("def");
        System.out.println(str);

    }
}
